Ballistic calculator

What I like to do on really hard shots, shooting from a mountain down into a valley or something like that is to use 3 different
calculators and look at all of them until I get them to agree pretty closely. You didn't say if you are shooting on flat ground, but I assume so. If you are shooting either up or down at an angle its big difference in ballistics. JBM is a good one, Gundata.org has a good one, and lately I like using Ballistics ARC cause you can pull in the weather with no more than 2 hrs. old, and even hook in your own kestrel for real time. Ballistics ARC uses JBM though. But getting 3 programs to agree is a little bit of a chore, but it works.

At the end of the day, none of the physics in these calculators is wrong. If you are off by 8 inches, there is an issue with your inputs, and you are just not seeing it. Get a buddy who is well versed in the ballistics calculators to go with you to the range, see what you are doing, look at your calcs, and see if another pair of good eyes who knows the programs the inputs can't help you resolve it.

Physics doesn't lie, especially on the vertical. It can be off in the horizontal a lot of times due to wind, wind tortuosity, and altitude/air density, and Barametric pressure. Make sure you are using "station pressure" if that's what your program asks for, not corrected Barametric Pressure at sea level which is what is commonly reported at airports and in weather reports. And a big no no is inputting barametric pressure that is in fact a station or local barametric pressure at your altitude and having the program correct it again because that is how the program inputs are set up. There is a whole thread here on the site you can read about the difference in Station Pressure and Weather channel Barametric Pressure. This is one of the most common traps of using ballistic calculators.

Same reason hunters that live at sea level sight in at 100 yards there and go hunt at 7000 feet in the mountains and wonder why their shots are going way over the backs of those Elk?

Good luck.
I don't usually use them all at the same time ,but I have all my data Trued in my G7 BR2 rangefinder my Shooter app and my kestrel they are all within one click of each other
 
@338 dude if you use his data what do you get for drop at 300 and 500 yards
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So he said he was dropping approximately 45 inches at 500 and 338's chart shows 8moa... by my math that's within 1-2 clicks.... not 6 or 7 so where's the issue again ?
 
So he said he was dropping approximately 45 inches at 500 and 338's chart shows 8moa... by my math that's within 1-2 clicks.... not 6 or 7 so where's the issue again ?
I'm getting about the same results, I'm still not clear why his original computation gave 1.8 MOA. Likely the atmosphere was wrong.
 

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I'm getting about the same results, I'm still not clear why his original computation gave 1.8 MOA. Likely the atmosphere was wrong.
I deleted the app, downloaded it again, input all of my current info at that particular time, and got different ballistics from what I had yesterday. Today it showed 2.62 at 300, which was still low.
 
I tried that also. It didn't work either. I'm doing something wrong, I just have to figure out what. I had gotten frustrated with the apps yesterday and just gave up. I'll start from scratch today and see if I can get it figured out.

29.9 baro 580 altitude
Thank you....Mils and Moa for certain!
 
I looked it up the BC is actually a G 1 at .424 so take a look at this DD Wing
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